The ambitious Serie A outfit cemented its European status, after it ran riot over Inter at the San Paolo.
A week after Javier Zanetti was confirmed as being sidelined for the remainder of 2013, Inter coach Andrea Stramaccioni was forced to reshuffle his back line. Fredy Guarin and Ricky Alvarez also had to be fielded as unorthodox forwards the wake of Inter's burgeoning injury list.
Walter Mazzarri had no such concerns on the night, starting Goran Pandev behind Serie A top scorer Edinson Cavani, and it was the pair who took responsibility for the Partenopei's early opener.
Pandev took control of a pass to release his strike partner, Cavani producing a masterful finish to slot the ball home. Despite the set back, the Inter came close to mustering a rapid fight back, Guarin's free kick then Alvaro Pereira's smart turn-and-shoot drawing difficult saves from Morgan De Sanctis.
Inter's endeavor was soon to pay off though, as a slick Mateo Kovacic ball found Alvarez advancing into the Napoli area, only to be barged down by the retreating Juan Zuniga. Alvarez picked himself up and promptly buried the spot kick into the low corner for a deserved 23rd minute equalizer.
Guarin tried once more to fire his side into the lead when he cut in from the flank and tested De Sanctis from an acute angle, but Samir Handanovic also had to be alert at the other end to thwart Blerim Dzemaili, who attempted to extend his recent scoring streak with a rising shot.
Zuniga eventually made up for his earlier mistake when he was brought to a crude halt by Jonathan in the Inter box. Cavani lined up the ensuing penalty, making no mistake from 12 yards for his 100th goal in Napoli colors.
Despite furtive penalty calls from Guarin and Zdravko Kuzmanovic, it was Handanovic who had to stay alert on Hamsik's attempt to prevent the scoreline from degenerating further before the halftime break.
Proccedings were brought back to life in the 66th minute when the San Paolo crowd rose in anticipation of Cavani getting on the end of Zuniga's pull back, but the Uruguay marksman made a hash of his shot to fire wide of the woodwork.
The in-demand striker was to swiftly make amends. Pandev made inroads down the left again, before swinging the ball into the center which a rash Handanovic completely misjudged, leaving Cavani with the simplest of tap ins to spark rapturous celebrations from the Napoli faithful.
Inter barely troubled Mazzarri's men until the final whistle, leaving the ambitious southern outfit to celebrate an assured return to the Champions League next season.
Inter's ninth away loss of the season leaves the club in a distant eighth position, with the prospects of European football diminishing very rapidly for Stramaccioni as the season draws to its close.